This appendix describes how to make your CA IDMS/DC Assembler program compatible with SNA protocols, allowing you to exchange information with other SNA-compatible products. The discussion will include information on:
What is SNA?
Systems Network Architecture (SNA) is a set of protocols and formats that enable different types of communications products to function together in a network environment. There are no specific SNA hardware or software products. Rather, SNA is a set of rules, an architecture, to which a wide variety of products can conform.
SNA/VTAM Line Driver
The CA IDMS/DC SNA/VTAM line driver (VTAMLU) is a task running under CA IDMS/DC that allows your task to communicate with other SNA-compatible devices. Many SNA logical units, for example, 3270 terminals and printers, can communicate using the standard CA IDMS/DC VTAM line driver (VTAMLIN). VTAMLIN handles most SNA protocols automatically, and should be used when possible for greater operating efficiency.
The CA IDMS/DC SNA/VTAM driver, and the material covered in this appendix, should be used with logical unit configurations that require special protocol control; for example, LU6.2 logical units, and IBM 4700 or 3700 devices. The SNA protocols enabled for a specific logical unit are defined through VTAM by bind parameters in a VTAM MODENT table. These bind parameters are the only way the CA IDMS/DC SNA/VTAM driver can determine which specific SNA protocols have been established for a logical unit; care should be taken to ensure that the bind parameters accurately reflect the capabilities of the logical unit.
Determining Compatibility and Need for Special Support
To determine whether SNA protocols for a given logical unit are compatible with those handled by the standard VTAM driver, or if they need special protocol support from the CA IDMS/DC SNA/VTAM driver, compare the bind parameter values in the MODENT table for your logical unit to those for a 3270 device. If the MODENT values are comparable to those for a 3270, it is probable that the standard VTAM driver can handle any SNA protocols for that logical unit.
Note: For more information about establishing bind parameters for a logical unit, see the System Generation Guide.
Support Offered by the SNA/VTAM Line Driver
The following table lists the LU types, function management profiles, and transmission service profiles that are supported by the CA IDMS/DC SNA/VTAM driver (LU 6 is not supported).
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SNA Protocol |
Types Supported by CA IDMS/DC |
|---|---|
|
LU Types |
0, 1, 2, 3, 4, 6.2 |
|
Function Management Profiles |
2, 3, 4, 7, 18, 19 |
|
Transmission Service Profiles |
2, 3, 4, 7 |
This section contains the following topics:
SNA Functions in a CA IDMS/DC Environment
Starting a Task from a Remote System
Synchronous and Asynchronous Processing
Responding to a Confirmation Request
Changing Direction: Send to Receive
Changing Direction: Receive to Send
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